The Expectation Value of a Many-Worlds Observable: A Multiworld Tale
by tonbotomoe
Summary: Their individual universes spiraled and revolved alongside and in parallel with each other. Experts on both worlds agree that the statistical probability of a collision is very nearly zero much less a meeting between a pirate with healing flames aboard a great ship and a scientist with earth at her palms and stars in her eyes. But here they were facing a storm together. How?


Haven't been edited so I shall do that before posting next chapter

Disclaimer: I don't own One Piece. Eiichiro Oda does.

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Mina grinned as she watched her young granddaughter make her way to her mountainside house through the window. 13-year old Kate was clutching a couple of books under her arm as she ran through craggy, rocky terrain on her way up her grandmother's little house on the foot of the mountain. From her vantage point, she could see the smudges of dirt across her cheeks and a blooming bruise on her knee and shin, surely the product of her usual afternoon spar at her mother's, Mina's daughter's, fighter school. Yet her spirited granddaughter grinned fearless and bright, sprinting to the tiny house without a care in the world. Mina's grin turned softer, mellower. All the years she has gained under her skin felt sharper and heavier in that one moment. She had the sudden urge to spread her wrinkled fingers and stare at the veins and the scars that had stayed with her all these years. She longed to press those same fingers to her heart, feel the remaining beats vividly as if to catch them, hold them, get back all the lives she has lived. Her lifetime has consisted all of 75 years but she felt like she has lived many lifetimes beyond that.

However, such efforts were futile. She knew that she didn't have much time left. Her time was too short for wistful thinking.

Instead, her eyes stayed trained on her granddaughter. She memorized the long fall of dark brown hair and the emerald green eyes sparkling with life and determination. Kate has always been a curious child, full of wonder and light. She had her quantum chemist father's sense of inquisitiveness about the world and her weapon master mother's stubbornness and tenacity to go after things nobody else did. She was gonna be brilliant.

Soon enough, Kate burst through the front door, eager to show her grandmother all the new things she learned about that day. Even at a young age, she has wanted to learn about everything. However, at 13, her heart has set on one thing. She hastily ran to her grandmother lounging at the couch nearest the window overlooking the mountains to the distance and the lake a foot away from the front door. She plopped down at the empty spot next to Mina, dumped her books on the floor, and proceeded to tell her beloved grandmother about her newfound passion.

She prattled on about stars: constellations and star systems and galaxies. She talked about how colors of the stars says something about their temperature. Her teacher has bemusedly taught the class about the lifetime of a star in details far too advanced for students her age after much prodding. The librarian she has pestered for the past month had finally yielded to her pleading and had conjured up a book about astrophysics. The first chapter started off by describing the beginning of the cosmos, life, and, well, everything: the Big Bang. Kate's eyes sparkled.

Kate kept on stumbling over foreign words that were still too big for her young tongue and her explanations were crude and shallow and surface-level at best. Technical details and sophisticated formulation will come with time, however, and Mina kept listening intent and contented.

But when Kate started talking about multi-world theories, Mina felt herself go rigid. Her veined, scarred, old fingers curled against her palm and her withered (yet still strong) beating heart stuttered. In our reality, the many worlds theory is at best an academic endeavor still too complex with implications still far too abstract even for the brightest scientific minds and at worst an impossibility only feasible in the realms of the imagination or fiction. But Mina and Kate didn't live in our world.

In their world of ninja arts, other-dimensional magical creatures, demonic spells, and alchemy, theories of other worlds existing alongside their own universe were not only within possibility but also a fundamental truth. Mina knew this firsthand, but she has lived so many lifetimes under her skin that she thought she has forgotten. She was amused at that, if a tad melancholy. Nostalgia can do that to you.

When Kate finally finished, Mina took her hand. "Do you want to hear a story?" she asked.

Kate blinked, nodded. Other than her father's scientific teachings and her mother's weapon training, Kate grew up on her grandmother's storytelling. As Kate aged, she grew closer and closer to her father's academic endeavors but her love for stories never waned. She liked the creativity and imagination that fueled them, the different other worlds that they opened up.

"What's it about?" Kate asked as she made herself comfortable curled up on her grandmother's lap, something else she wasn't ready to grow up from. Mina thought of an answer.

"Something real. A memory, perhaps? Hmm, maybe not. Maybe just a dream, then. You decide, my love." A story. A choice, A whole new world. This would be Mina's legacies to her granddaughter. She has given her daughter a new life, a chance to start over. To her grandsons, Kate's 3 older brothers, she has given them all her love and her care. Her support was a strength that helped sustain them to adulthood. She was very much saddened that she couldn't do the same for Kate. Instead, she had one last thing to give. Kate was going to be, was already, brilliant. She would know what to do when the time comes.

"It all started with a man. Even when he was still so young, I knew he was gonna be a great man. He was already a giant even when we were young..." As Kate listened, Mina plunged deeper and deeper into the past until memories fell easily around them like snow.

In another world running parallel to Mina's and Kate's, a great man leaned back against the rails framing the deck of a formidable ship to look up at the night sky. The ship was currently anchored at the bay of an island, one amongst thousands littered all along a tumultous ocean called the Grand Line. It was a Spring island so the night air blew gently and warmly with a touch of blossom fragrance mixed with the smells of the sea. The island was tiny, ordinary, and insignificant but the greatest man that this great man knew looked deeply at insignificant things and saw things nobody else can. His captain saw a typical agricultural economy masking the significance of their region's variety of trees with saps that had medicinal properties and he saw fiercely independent citizenry that struggled to protect their way of life as waves of pirates and marines alike threatened to plunder and exploit their home. And really most of the time that was all his noble captain needed to rise to their aid and defend this tiny island with all his strength. Of course, his crew of unruly, rough, yet good at heart pirates would always follow to battle. The Whitebeard pirates were rogues, outcasts, and scoundrels but their Pops gave them a family to belong to and a purpose to bury their hands in and they would carry these new responsibilities all the days of their lives.

As in typical fashion, after the battle was fought and all the scum were driven out, Captain Whitebeard proclaimed this island, named Berry Berry Island, as his territory and partying commenced. The party raged late into the night until the last person passed out from both exhaustion and alcohol.

As in typical fashion, Marco the Phoenix sighed, rolled his eyes, scratched his blonde tuft of hair, and left his crew, his captain, the island people still remaining (kids were already tucked into beds and the nurses in all their pragmatism and endless wisdom has turned in early knowing that they would have their hands full with crew and citizen alike suffering from blaring hangovers in the morning) snoring and contented alongside each other and climbed aboard the Moby Dick's deck to watch the stars.

If there was one great thing in a world made of oceans, all of two big landmasses of any significance, and islands spread far apart, it was that stargazing would never be a problem. In fact, it was one of the favorite hobbies that Marco, first division commander, head navigator, disgruntled quartermaster, and unofficial first mate, indulged in almost every night. He had grown up hungry for knowledge of the world around him and had consumed maps and books that had drifted to his small Summer island home. The first story he ever read was a collection of stories about different constellations. The second information about navigation he has ever learned was how stars can be used as navigational tools. After that, he would climb the roof of his tree house, would look up at the points of lights that could lead sailors home, and would talk to them like they were old friends. They never answered back but to a young lonely introverted orphan with no past and a foggy, the way they twinkled bright constantly and reliably was something to hold on to. Even when he left and gained family and friends to talk to and who had stood with him shoulder to shoulder and back to back for every battle and adventure, his little ritual continued. He had decided long ago that it won't ever stop.

Tomorrow, he would wake his fellow crew members up and help herd them to the sick bay. In the days that would follow there would be pirate enemies to fight, islands and people to defend, and the World Government to face. There were also the daily annoyances that came with organizing, cleaning up, and smoothing over the fine details of running a pirate ship (Pops was their fierce leader, the one who made the tough decisions and who had the final say but it was Marco who had the tough job of being the captain's shadow who took care of the messy, trivial minutiae of the Moby Dick). There were also a lot of adventuring, drinking, partying, and quite a lot of treasure still to come.

But for the moment he would greet his old friends and tell them of his secrets: his fears, his worries, and his heartfelt joy and pride. _"Pops has gotten more stubborn the older he grows. Does he not worry about keeling over on us at all? He's the strongest man in the world but I never forget that he's still mortal. Old man needs to look after his health more."_ and _"We promoted a new commander recently. Haruta's still young and acts younger than his age most of the time. Kinda childish and a bit spoiled, that one. But I think he'll do well since he has so much spirit and fire in him. Might as well channel all that to something productive. Maybe get a vet to whip him into shape? Speaking of there's still nobody to lead the second division..."_ and _"That stupid Thatch how the hell is he my best friend again?"_

As Marco the Phoenix he stood tall in the battlefield, his flaming blue wings a shining beacon. As first division commander and the closest thing to Whitebeard's eldest, he stood strong as a pillar of solidarity for his younger brothers. But as he gazed at the vast immensity of the universe, he felt very tiny, very ordinary, and very insignificant indeed.


End file.
